Space is hardly the final frontier when it comes to human exploration.

All around us are the oceans, a vast and unmapped region teeming with life that is largely undiscovered. The amount of stuff that science doesn’t know about the world’s oceans could literally fill an ocean.

Creatures of the Deep

Most of the species that live in the ocean are unknown to us. According to a study that was featured in the journal Biology, the oceans are home to up to one million different species.

Of them, around two-thirds have yet to be discovered. In many ways, the world’s oceans are a mysterious realm of possibility that humans have barely begun to explore.

There is so much unknown life in the oceans, an average of 200 new ocean species are discovered every year and we’ve still barely scratched the surface.

What You Never Knew

The oceans cover about 70 percent of the surface of the Earth, and yet there are so many unknowns about the mysteries lurking beneath those blue waves.

The deepest part of the oceans, the Mariana Trench, extends 7 miles below the surface of the water.

To put that into perspective, Mount Everest could fit down in the trench with room to spare.

Manned explorations of the trench have never descended deeper than 35,797 feet below the surface.

Entire ecosystems exist under the surface of the oceans, including lakes, rivers, mountain ranges, volcanoes, and waterfalls.

The most impressive waterfall in the entire world lies beneath the surface of the ocean. The Denmark Strait is a waterfall with an 11,500-foot drop that makes Niagara Falls look like a trickle.

More to Discover

One oceanographer has estimated that humans have actually explored less than 10 percent of the planet. But for humans, it’s extremely difficult to explore the deep areas of the ocean and we have yet to successfully map the entire ocean floor.

Equipment makes it possible to get a general idea of what’s down there, but even the most sophisticated technology doesn’t provide detail.

The U.S. National Ocean Service says that more than 80 percent of the ocean is “unmapped, unobserved, and unexplored,” an idea that’s both thrilling and chilling. An untold number of shipwrecks and air wrecks lay on the floor of the ocean, out of sight and out of reach.

Legend hints that the remnants of fabulous cities, like the mythic Atlantis, lay waiting down here in the darkness as well. The ocean could hold the keys to some of history’s greatest mysteries.

Sleeping Secrets

Humans have explored about 5 percent of the ocean floor. The other 95 percent has never been seen by human eyes.

There are canyons wider and deeper than the Grand Canyon, incredible valleys, lakes that are more than 300 feet deep and species no person has ever seen hiding under the waters of the ocean.

The plant and animal life that exists here is incredibly varied and may answer all sorts of questions we have about our world.

But we’ll have to find them first.

Humans are not built to spend extended periods of time underwater, which puts an enormous amount of pressure on the body.

The temperatures in the ocean also vary widely, getting as hot at 750 degrees F in some places near underwater volcanoes.

The ocean remains a place of shadowy, hidden mysteries that humans can’t yet reach. That makes the possibilities tantalizing and thrilling.